1. Field of the Invention
The present invention relates generally to water treatment systems and, more particularly, to a water treatment system which utilizes aqueous sulfurous acid produced by a solid sulfur-based sulfurous generator for further treatment of the water.
2. Description of the Prior Art
In wastewater treatment facilities, a main stream of wastewater typically is treated with a chlorine-containing compound, such as sodium hypochlorite, to neutralize bacteria in the wastewater stream. It is undesirable to under treat the wastewater stream because active bacteria will thus remain in the wastewater stream. It is also undesirable to over treat the wastewater with chlorine because a residual chlorine level in the wastewater stream will be detrimentally high. Additionally, the chlorine or other treatment fluid is wasted and additional chemical is typically needed to neutralize the excess chlorine.
Wastewater treatment facilities can incur fines for releasing wastewater, which is either under treated or over treated with chlorine containing compounds. Wastewater treatment facilities additionally suffer financially from the unnecessary use of excess chlorine and chlorine neutralizing chemicals, such as sulfur dioxide when the chlorination/de-chlorination process is not operating optimally.
Many advanced wastewater treatment systems include a residual chlorine analyzer downstream from the chlorinator, which monitors the levels of chlorine residual remaining in the wastewater stream. One such system is disclosed in U.S. Pat. No. 6,346,198, issued to Watson et al., which is hereby incorporated by reference in its entirety. Controllers may utilize the results of this downstream analyzer to provide a feedback signal to the chlorinator. In essence, if an amount of residual chlorine is too high at the downstream analyzer, the chlorinator receives a feedback signal, which decreases the rate of introduction of chlorine. If the analyzer detects that no chlorine or too little chlorine remains, indicative that not all of the bacteria has been neutralized, the feedback signal may cause the chlorinator to increase the rate with which it introduces chlorine.
When compressed sulfur dioxide gas is used to neutralize the excess chlorine, there is not only its cost but also the danger associated with its use. Sulfurous acid generators have been used for other water treatment applications such as treating the irrigation water used by golf courses and agricultural facilities. Two such generators are described in U.S. Pat. No. 4,526,771, issued to Forbush et al. and U.S. Pat. No. 6,248,299, issued to Jackson. Both of these patents are hereby incorporated by reference in their entirety. However, these generators are not adapted for wastewater treatment nor do they typically include the necessary safety systems that would be required.
Thus, there remains a need for a new and improved water treatment system which utilizes aqueous sulfurous acid produced by a solid sulfur-based sulfurous generator for further treatment of the water while, at the same time, includes a shut-off safety system to prevent leakage of molten sulfur from the sulfurous generator.